1. Field of the Invention
The present invention relates generally to well cleaning systems and more particularly to in-well cleaning apparatus.
2. Description of Related Art
Sewage systems are in wide spread use for the removal of liquid waste from houses, factories and agricultural sites. The sewage flows through pipes into intermediate wells and finally into treatment plants or waste dumps. Electric pumps are usually used to maintain the flow and keep the wells below maximum capacity. These pumps are configured to operate when the level in the wells reaches a preset limit indicating that the flow needs pumping.
When the well level falls to a minimum level the pump is switched off and this level may be maintained for some time leaving a biofilm residue on the walls of the well between the maximum and minimum levels. This residue tends to harden and build up thus reducing the capacity of the well, and increasing the frequency of the pump operation.
Wastewater collection and treatment systems are a source of bad odors, the most prevalent coming from Hydrogen Sulphide, a toxic and corrosive gas with a characteristic rotten-egg smell. This is a bacterially mediated process that occurs in the submerged portion of sanitary sewerage systems. It begins with the establishment of a slime layer below the water level, composed of bacteria and other inert solids held together by a biologically secreted protein “glue” or biofilm called zooglea. When this biofilm becomes thick enough to prevent the diffusion of dissolved oxygen, an anoxic zone develops under the surface.
Hydrogen Sulphide is also a precursor to the formation of Sulphuric Acid, which causes the destruction of metal and concrete substrates and appurtenances within wastewater facilities and collection stations. The effect of biogenic sulfide corrosion and the formation of a 7% Sulphuric Acid solution on concrete surfaces exposed to the sewer environment are devastating. Entire pump stations and manholes and large sections of collection interceptors have collapsed due to the loss of structural integrity in the concrete. Accordingly the residue must be cleaned off the well walls and removed from the surface of the sewer water periodically to maintain the system in good working order as well as protecting concrete structures against the biogenic sulfide corrosion in wastewater collection and treatment systems so as to met the structure's anticipated design life as well as protecting the surrounding ground level infrastructure and environment.